Evaluation of minority carrier lifetime in BaSi2 as a novel material for earth-abundant high efficiency thin film solar cells

We investigated minority carrier lifetime in 100-nm-thick a-axis oriented BaSi₂ thin films on Si(111) using a differential microwave photoconductivity decay system. The excitation wavelength was chosen as 349 nm so that photocarriers are generated not in the Si substrate but in the thin film. From the decay profile of the microwave, 1/e decay time was revealed to be in the order of μsec. This would correspond to the minority carrier diffusion length in the order of μm, which shows that BaSi₂ is promising as a novel material for earth-abundant, high-efficiency thin film solar cells.